Posted by **joshua** on Sunday, December 30, 2012 at 4:47pm.

1. If $ is defined for all positive numbers x and y by x$y = 3x + 8y - y^3, then 10$2 =

A. 38

B. 102

C. 14

D. 20

2. If & is defined for all positive numbers w and z by w & z = 15wz - 10w + 2 then 3 & 4 =

A. 67

B. 77

C. 142

D. 152

3. All of the following are in the domain of f(x) = 5/ x + 2 except:

A. 5

B. -5

C. 2

D. -2

could you explain to me how to get the answer for them

- mathematics -
**Reiny**, Sunday, December 30, 2012 at 5:02pm
1 and 2

the operations are defined, so just sub in as defined.

1.

10$2 = 3(10) + 8(2) - 2^3 = ....

same for #2

3. f(x) = 5/x + 2

the function is defined for all real values of x, except x = 0

This is not one of your choices, so the question is bogus.

If you meant f(x) = 5/(x+2) , then the function is defined for all real values of x, except x = -2

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